EP0211582A2 - Filtre à base d'une fibre optique - Google Patents

Filtre à base d'une fibre optique Download PDF

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Publication number
EP0211582A2
EP0211582A2 EP86305727A EP86305727A EP0211582A2 EP 0211582 A2 EP0211582 A2 EP 0211582A2 EP 86305727 A EP86305727 A EP 86305727A EP 86305727 A EP86305727 A EP 86305727A EP 0211582 A2 EP0211582 A2 EP 0211582A2
Authority
EP
European Patent Office
Prior art keywords
fibre
power
optical fibre
elongating
filter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86305727A
Other languages
German (de)
English (en)
Other versions
EP0211582A3 (fr
Inventor
Anthony Christos Boucouvalas
George Antony Georgiou
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co PLC
Original Assignee
General Electric Co PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co PLC filed Critical General Electric Co PLC
Publication of EP0211582A2 publication Critical patent/EP0211582A2/fr
Publication of EP0211582A3 publication Critical patent/EP0211582A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/255—Splicing of light guides, e.g. by fusion or bonding
    • G02B6/2552—Splicing of light guides, e.g. by fusion or bonding reshaping or reforming of light guides for coupling using thermal heating, e.g. tapering, forming of a lens on light guide ends
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02052—Optical fibres with cladding with or without a coating comprising optical elements other than gratings, e.g. filters

Definitions

  • the present invention relates to optical fibre filters.
  • An optical fibre normally has a relatively broad wavelength transmission characteristic. Depending upon the dimensions and refractive index profile of the fibre, there will be a cut-off wavelength beyond which the HE21 mode will not propagate along the fibre. Shorter wavelengths will normally propagate and the loss of the fibre will vary according to the wavelength being transmitted.
  • the present invention therefore relates to the technical problem of producing an optical fibre filter.
  • the present invention provides a method of producing an optical fibre filter comprising the steps of launching light energy of a single wavelength into an optical fibre, elongating a portion of the fibre while monitoring the power transmitted therethrough, and stopping the elongating process at a selected point of the transmitted power/elongation curve.
  • the method is particularly advantageous in that it enables filters of different characteristics to be produced from an optical fibre without any strict fabrication requirement for the starting fibre.
  • the invention further provides apparatus for producing an optical fibre filter comprising a laser source producing radiation at a single wavelength for propagation along an optical fibre, means for elongating a portion of the fibre, means for monitoring the power transmitted along the fibre through the elongated portion, and means for controlling the elongating means in response to the output of the power monitoring means so as to stop the elongation at a predetermined point in the relationship between power and elongation.
  • Figure 2 illustrates the apparatus used for producing the taper in a fibre 10.
  • the apparatus comprises a laser light source producing radiation at a predetermined wavelength which is 1. 5 micrometres for the purposes of the present example.
  • This radiation is passed through a lens 14 to focus it onto the cleaved face of the core 2 of the fibre 10 so that light is propagated along the core of the fibre.
  • the fibre will be surrounded by an acrylate jacket which will strip any modes which start to propagate in the cladding waveguide of the fibre. If such a jacket is not provided the fibre may pass through a bath of index matching fluid which will prevent light propagation along the cladding waveguide.
  • the fibre 10 is clamped at two spaced points along its length by clamps 16 and 18.
  • Each clamp is provided with a motorised driver 20, 22 to enable the clamps to be pulled away from each other to taper the portion of the fibre between them.
  • the drives are precisely controlled so that fibre extension of the order of 1cm can be achieved and the extension stopped at a desired point to an accuracy of less than 1mm.
  • the clamps may be positioned vertically one above the other so that gravity can assist the tapering process.
  • An epoxy-butane flame (not shown) is used to heat the fibre while the taper between the clamps is elongated.
  • the end of the fibre 10 is coupled to a power detector 24 which is connected to a chart recorder. If this is not the case then the power detection is provided by a microscope coupled to a vidicon camera. The power detector or microscope is focused so as to detect the power propagated along the core of the optical fibre 10. If the acrylate jacket does not strip modes propagating in the cladding waveguide, a further bath of index matching fluid is provided to avoid light propagating in the cladding waveguide affecting the power detector.
  • a typical plot produced on the chart recorder 26 is shown in Figure 1.
  • the plot comprises a level section where a constant amount of power is being received.
  • the power launched from the laser into the core is being propagated along the core with little- or no coupling of power into the cladding waveguide.
  • the received power oscillates increasingly rapidly between a series of minima A, B, C where little power is being received through the core.
  • minima correspond to extensions of the fibre at which the tapered portion of the fibre 10 between the clamps 16, 18 is so dimensioned that there is complete energy coupling between the core and the cladding waveguides.
  • the plot produced in Figure 1 has been shown for a considerable extension of the fibre between the clamps.
  • the drive to the clamps is stopped when the recorder reaches one of the minimum A, B, C or a desired intermediate point depending on the required wavelength transmission characteristic of the filter.
  • Figure 3 shows plots of the wavelength transmission characteristics in which power transmitted is plotted against wavelength for optical fibre filters produced by stopping the taper at various extensions when laser light of 1.5 micrometres is being propagated along the fibre core.
  • Figure 3A shows the transmission characteristic of the filter produced by stopping the taper at the point marked A on Figure 1.
  • the maximum to minimum transmission points are separated by 280 nanometres and the modulation depth is at least 14dB.
  • the transmission characteristic illustrated in Figure 3B is produced as a result of stopping the extension approximately at the point marked B in Figure 1. In this transmission characteristic the full oscillation is clear.
  • the pass band is now 220 nanometres wide and at least 33dB modulation is present.
  • the iflter has a pass band of 190 nanometres which is 33.5dB deep.
  • the pass band is reduced to 165 nanometres with a modulation depth of 41dB.
  • Optical fibre filters with different characteristics can be produced in dependence on the point on the power/elongation curve at which tapering is stopped, and on the value of the single wavelength used to generate the curve. Where the taper is stopped at a minimum, the resulting filter will normally block radiation of the single wavelength used to produce the curve; this is because at a minimum of the power/elongation curve energy at that wavelength is coupled to the tubular cladding waveguide. If elongation is stopped at a maximum, the single wavelength will be within the pass band.
  • Optical filters produced by the described method can readily be incorporated into an optical fibre system where they will filter out wavelengths outside the pass band and transmit the filtered energy through the optical fibre system with minimum loss.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Light Guides In General And Applications Therefor (AREA)
  • Laser Surgery Devices (AREA)
EP86305727A 1985-07-29 1986-07-25 Filtre à base d'une fibre optique Withdrawn EP0211582A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8519087 1985-07-29
GB858519087A GB8519087D0 (en) 1985-07-29 1985-07-29 Optical fibre filters

Publications (2)

Publication Number Publication Date
EP0211582A2 true EP0211582A2 (fr) 1987-02-25
EP0211582A3 EP0211582A3 (fr) 1987-11-11

Family

ID=10583016

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86305727A Withdrawn EP0211582A3 (fr) 1985-07-29 1986-07-25 Filtre à base d'une fibre optique

Country Status (2)

Country Link
EP (1) EP0211582A3 (fr)
GB (2) GB8519087D0 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2299683A (en) * 1995-04-04 1996-10-09 Northern Telecom Ltd Optical notch filter manufacture in a single mode fibre
EP0793124A1 (fr) * 1996-03-01 1997-09-03 Alcatel Filtre obtenu par inscription d'un réseau de Bragg dans une fibre optique
US6459526B1 (en) 1999-08-09 2002-10-01 Corning Incorporated L band amplifier with distributed filtering
DE102006002605A1 (de) 2006-01-13 2008-07-24 Technische Universität Berlin Optisches Modul mit einer Lichtleitfaser und einer Fabry-Perot Schichtstruktur als elektrooptischer Modulator und abstimmbares Filter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3957341A (en) * 1974-09-03 1976-05-18 The United States Of America As Represented By The Secretary Of The Navy Passive frequency-selective optical coupler
GB1493660A (en) * 1975-12-16 1977-11-30 Standard Telephones Cables Ltd Optical waveguide power dividers
CA1118621A (fr) * 1979-11-01 1982-02-23 Lawrence C. Smyth Methode et gabarit de fabrication de raccords pour fibres optiques
EP0123396A2 (fr) * 1983-03-22 1984-10-31 THE GENERAL ELECTRIC COMPANY, p.l.c. Fabrication de coupleurs de fibres optiques
EP0148569A1 (fr) * 1983-11-30 1985-07-17 Stc Plc Fabrication d'un coupleur directionnel à fibres monomodes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3957341A (en) * 1974-09-03 1976-05-18 The United States Of America As Represented By The Secretary Of The Navy Passive frequency-selective optical coupler
GB1493660A (en) * 1975-12-16 1977-11-30 Standard Telephones Cables Ltd Optical waveguide power dividers
CA1118621A (fr) * 1979-11-01 1982-02-23 Lawrence C. Smyth Methode et gabarit de fabrication de raccords pour fibres optiques
EP0123396A2 (fr) * 1983-03-22 1984-10-31 THE GENERAL ELECTRIC COMPANY, p.l.c. Fabrication de coupleurs de fibres optiques
EP0148569A1 (fr) * 1983-11-30 1985-07-17 Stc Plc Fabrication d'un coupleur directionnel à fibres monomodes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
IEEE JOURNAL OF QUANTUM ELECTRONICS, vol. QE-10, no. 12, December 1974, pages 879-887, New York, US; S. KAWAKAMI et al.: "Characteristics of a doubly clad optical fiber with a low-index inner cladding" *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2299683A (en) * 1995-04-04 1996-10-09 Northern Telecom Ltd Optical notch filter manufacture in a single mode fibre
US5708740A (en) * 1995-04-04 1998-01-13 Northern Telecom Limited Optical notch filter manufacture in optical fibre waveguide by plastic deformation
EP0793124A1 (fr) * 1996-03-01 1997-09-03 Alcatel Filtre obtenu par inscription d'un réseau de Bragg dans une fibre optique
FR2745641A1 (fr) * 1996-03-01 1997-09-05 Alcatel Submarcom Filtre obtenu par inscription d'un reseau de bragg dans une fibre optique
US5818987A (en) * 1996-03-01 1998-10-06 Alcatel Alsthom Compagnie Generale D'electricite Filter obtained by writing a Bragg grating into an optical fiber
US6459526B1 (en) 1999-08-09 2002-10-01 Corning Incorporated L band amplifier with distributed filtering
DE102006002605A1 (de) 2006-01-13 2008-07-24 Technische Universität Berlin Optisches Modul mit einer Lichtleitfaser und einer Fabry-Perot Schichtstruktur als elektrooptischer Modulator und abstimmbares Filter

Also Published As

Publication number Publication date
GB8618182D0 (en) 1986-09-03
EP0211582A3 (fr) 1987-11-11
GB2179172B (en) 1989-08-16
GB2179172A (en) 1987-02-25
GB8519087D0 (en) 1985-09-04

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Inventor name: BOUCOUVALAS, ANTHONY CHRISTOS